Active Thermal Nondestructive Inspection of Electric Railway Poles

Results of practical IR thermographic inspection of railway concrete poles with longitudinal and transverse reinforcement are described. Thermal stimulation was performed by applying an inductor with the power of 12 kW, and the temperature was recorded with FLIR P65 and Testo 875 IR imagers. Defect-free poles revealed high-contrast temperature indications of reinforcement. Electro-corrosion damage in lower sections of some inspected poles was characterized by lower temperatures and lower rates of temperature variation in time. The results of active thermal testing were compared with those obtained by visual and acoustic inspection.